Method for manufacturing ceramic electronic component and gravure printing method

ABSTRACT

A method for manufacturing a ceramic electronic component includes first and second gravure-printing steps in which conductive paste and step-reducing ceramic paste are printed on a composite sheet including a ceramic green sheet. A first print mark is printed before the second gravure-printing step is performed, and the position of the first print mark is determined and compared with a desired position of the first print mark before the second gravure-printing step. Then, the second gravure-printing step is performed such that a second print mark is printed at a suitable position with respect to the position of the first print mark.

This application is a Divisional Application of U.S. patent applicationSer. No. 10/759,111 filed Jan. 20, 2004, now U.S. Pat. No. 7,047,880.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to methods for manufacturing ceramicelectronic components such as multilayer capacitors, and morespecifically, to a method for manufacturing a ceramic electroniccomponent including an improved gravure-printing step in whichconductive paste is printed on a ceramic green sheet.

2. Description of the Related Art

In a manufacturing process of, for example, a multilayer ceramiccapacitor, a gravure-printing method is used for printing ceramic pasteand conductive paste on a ceramic green sheet disposed on a supportingfilm.

Japanese Unexamined Patent Application Publication No. 8-250370discloses a method for manufacturing a multilayer ceramic capacitor inwhich a plurality of internal electrode patterns are formed on adielectric green sheet disposed on a long supporting film by gravureprinting using a first gravure roll and a step-reducing dielectricpattern is formed so as to fill the spaces between the internalelectrode patterns by gravure printing using a second gravure roll.

In the above-described method in which the internal electrode patternsand the step-reducing dielectric pattern are formed on the longdielectric green sheet using the gravure rolls, displacement along thewidth of the dielectric green sheet (displacement in a directionperpendicular to the conveying direction of the dielectric green sheet)often occurs.

In the case in which the internal electrode patterns and thestep-reducing dielectric pattern are printed on the dielectric greensheet as described above, when the displacement along the width of thedielectric green sheet occurs, the internal electrode patterns and thestep-reducing dielectric pattern are not formed at desired locationssince the internal electrode patterns and the step-reducing dielectricpattern overlap each other or intervals between them are excessivelyincreased.

Therefore, the displacement along the width of the dielectric greensheet is corrected before the second gravure-printing step by moving thesecond gravure roll along its axis, that is, along the width of thedielectric green sheet.

Therefore, as shown in FIG. 17, a distorted step-reducing dielectricpattern 101 b is produced depending on the timing of the movement of thegravure roll. With reference to FIG. 17, a long dielectric green sheet102 is disposed on a supporting film, and the supporting film isconveyed in a direction shown by the arrow A. In addition, a printdirection is shown by the arrow B, and a position at which the gravureroll is moved is denoted by C. Each of print patterns 101 a, 101 b, and101 c is printed by a single turn of the gravure roll.

In addition, there is also a problem in that the thickness of thestep-reducing dielectric pattern 101 b changes depending on the time atwhich the gravure roll is moved.

When the distortion and the change in thickness of the step-reducingdielectric pattern occur as described above, the step-reducingdielectric pattern does not provide its intended purpose, which is toeliminate the steps around the internal electrode patterns, andstructural defects of the laminate such as delamination may occur.

In addition, similar to the above-described gravure-printing method forprinting the conductive paste and the step-reducing ceramic paste in theprocess of manufacturing the multilayer ceramic capacitor, a multicolorgravure-printing method also has a problem in that a displacement occursand high-definition multicolor printing is difficult.

SUMMARY OF THE INVENTION

In order to overcome the problems described above, preferred embodimentsof the present invention provide a method for manufacturing a ceramicelectronic component including a step of applying conductive paste on asheet or step-reducing ceramic paste by gravure printing, by which thedisplacement is corrected with high accuracy and distortion of thestep-reducing ceramic paste and the conductive paste is prevented.

A method according to a first preferred embodiment of the presentinvention includes a preparation step of preparing a long compositesheet including a supporting film and a ceramic green sheet disposed onthe supporting film, a first gravure-printing step of applying a firstpaste to the ceramic green sheet in a first region of the ceramic greensheet by gravure printing, and a second gravure-printing step ofapplying a second paste to the ceramic green sheet in a second region ofthe ceramic green sheet by gravure printing, and a first print mark isformed on the ceramic green sheet or the supporting film in the firstgravure-printing step. The position of the first print mark formed inthe first gravure-printing step is compared with a desired position ofthe first print mark, and the second gravure-printing step is performedin accordance with the result of the comparison.

As described above, according to the first preferred embodiment of thepresent invention, the position of the first print mark which is formedin the first gravure-printing step is compared with the desired positionof the first print mark after the first gravure-printing step, and thesecond gravure-printing step is performed in accordance with the resultof the comparison. Therefore, when the first and the second pastes areapplied to the ceramic green sheet or the supporting film in the firstand the second gravure-printing steps, respectively, print patternsformed in the second gravure-printing step are positioned with highaccuracy with respect to print patterns formed in the firstgravure-printing step.

In the method for manufacturing the ceramic electronic componentaccording to the first preferred embodiment of the present invention,the second gravure-printing step is performed after the ceramic greensheet is moved along the width and/or the length thereof in accordancewith the result of the comparison or while the ceramic green sheet isbeing moved along the width and/or the length thereof in accordance withthe result of the comparison.

When the second gravure-printing step is performed after the ceramicgreen sheet is moved or while it is being moved along the width and/orthe length in accordance with the difference between the position atwhich the first print mark is formed and the desired position of thefirst print mark, print patterns formed in the second gravure-printingstep are positioned with high accuracy with respect to print patternsformed in the first gravure-printing step.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the first preferred embodiment of the presentinvention, a first imaging device and a first image-processing deviceare preferably used for determining the position of the first printmark. In this manner, the position of the first print mark is determinedwith high accuracy.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the first preferred embodiment of the presentinvention, a second print mark is preferably formed on the ceramic greensheet or the supporting film in the second gravure-printing step. Inthis manner, the positions of the first and the second print marksformed in the first and the second gravure-printing steps, respectively,are compared with desired positions of the first and the second printmarks, and the second gravure-printing step is repeated in accordancewith the result of the comparison.

In such a case, the position of the ceramic green sheet is adjusted byfeedforward control after the first gravure-printing step, and then thepositions of the first and the second print marks are adjusted with highaccuracy by feedback control after the second gravure-printing step onthe basis of the actual positions of the first and the second printmarks. Accordingly, the first and the second gravure-printing steps areperformed with higher accuracy.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the first preferred embodiment of the presentinvention, a second print-mark-printing element provided on a platecylinder used in the second gravure-printing step is preferably detectedfor determining the position of the second print mark.

When the position of the second print mark formed on the ceramic greensheet or the supporting film is determined by detecting the secondprint-mark-printing element provided on a plate cylinder used in thesecond gravure-printing step and the first or the secondgravure-printing step is performed in accordance with the result ofcomparison between the desired positions of the first and the secondprint marks and the actual positions thereof, the positions of the firstand the second print marks are determined and compared with the desiredpositions more quickly. Therefore, the position of the ceramic greensheet is adjusted more quickly for the second gravure-printing step.

According to a second preferred embodiment of the present invention, amethod for manufacturing a ceramic electronic component includes apreparation step of preparing a long composite sheet including asupporting film and a ceramic green sheet disposed on the supportingfilm, a first gravure-printing step of applying a first paste to theceramic green sheet in a first region of the ceramic green sheet bygravure printing, and a second gravure-printing step of applying asecond paste to the ceramic green sheet in a second region of theceramic green sheet by gravure printing, and a first print mark isformed on the ceramic green sheet or the supporting film in the firstgravure-printing step. The transit time of the first print mark formedin the first gravure-printing step is compared with a desired transittime of the first print mark, and the second gravure-printing step isperformed in accordance with the result of the comparison.

As described above, according to the second preferred embodiment of thepresent invention, the transit time of the first print mark formed inthe first gravure-printing step is compared with the desired transittime of the first print mark and the second gravure-printing step isperformed in accordance with the result of the comparison. Therefore,similar to the first preferred embodiment of the present invention, theprint patterns formed in the second gravure-printing step are positionedwith high accuracy with respect to the print patterns formed in thefirst gravure-printing step.

In the method for manufacturing the ceramic electronic componentaccording to the second preferred embodiment of the present invention,the second gravure-printing step is performed after the ceramic greensheet is moved along the width and/or the length thereof in accordancewith the result of the comparison or while the ceramic green sheet isbeing moved along the width and/or the length thereof in accordance withthe result of the comparison.

When the second gravure-printing step is performed after the ceramicgreen sheet is moved or while it is being moved along the width and/orthe length in accordance with the difference between the actual transittime of the first print mark and the desired transit time thereof suchthat the second print mark is printed after the first print mark with atime difference between the desired transit time of the first print markand that of the second print mark, the print patterns formed in thesecond gravure-printing step is positioned with high accuracy withrespect to the print patterns formed in the first gravure-printing step.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the second preferred embodiment of the presentinvention, a first sensor and a first measuring device are preferablyused for determining the transit time of the first print mark. In thismanner, the transit time of the first print mark is determined with highaccuracy.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the second preferred embodiment of the presentinvention, a second print mark is preferably formed on the ceramic greensheet or the supporting film in the second gravure-printing step. Inthis manner, the transit times of the first and the second print marksformed in the first and the second gravure-printing steps, respectively,are compared with desired transit times of the first and the secondprint marks, and the second gravure-printing step is repeated inaccordance with the result of the comparison.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the first or the second preferred embodiments ofthe present invention, the dimension of the first print mark and/or thesecond print mark along the length of the ceramic green sheet preferablychanges along the width of the ceramic green sheet. In this manner, thetransit times of the first and the second print marks are easilydetermined with a simple sensor.

In addition, in the method for manufacturing the ceramic electroniccomponent according to the first or the second preferred embodiments ofthe present invention, the first paste and the second paste are aconductive paste and a step-reducing ceramic paste, respectively, orboth of the first paste and the second paste are a conductive paste.

Other features, elements, characteristics, steps and advantages of thepresent invention will become more apparent form the following detaileddescription of preferred embodiments with reference to the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic plan view showing print patterns and first andsecond print marks printed in first and second gravure-printing steps,FIG. 1B is a schematic plan view showing the first print mark, and FIG.1C is a schematic plan view showing the relationship between the firstand the second print marks;

FIG. 2 is a schematic diagram showing a device for determining thepositions of the first and the second print marks according to apreferred embodiment of the present invention;

FIG. 3 is a schematic perspective view showing displacement of a secondgravure roll along its axis;

FIG. 4 is a schematic diagram showing an apparatus for performing thefirst and the second gravure-printing steps used in preferredembodiments of the present invention;

FIGS. 5A and 5B are perspective views of first and second gravure rolls,respectively;

FIG. 6 is a schematic diagram showing a device for moving the secondgravure roll along its axis according to preferred embodiments of thepresent invention;

FIG. 7 is a schematic plan view showing the state after a ceramic greensheet disposed on a supporting film is subjected to the first and thesecond gravure-printing steps according to preferred embodiments of thepresent invention;

FIG. 8 is a schematic sectional view showing the state after conductivepaste and step-reducing ceramic paste are printed on the ceramic greensheet disposed on the supporting film in the first and the secondgravure-printing steps according to preferred embodiments of the presentinvention;

FIG. 9A is a sectional view of a mother laminate obtained in preferredembodiments of the present invention, and FIG. 9B is a sectional view ofa multilayer ceramic capacitor obtained in preferred embodiments of thepresent invention;

FIG. 10 is a schematic diagram showing a device for determining thepositions of first and second print marks according to a firstmodification of preferred embodiments of the present invention;

FIG. 11 is a schematic plan view of the first print mark printed in thefirst modification of preferred embodiments of the present invention;

FIG. 12 is a schematic plan view of the second print mark printed in thefirst modification of preferred embodiments of the present invention;

FIG. 13 is a schematic diagram showing a device for determining thepositions of first and second print marks according to a secondmodification of preferred embodiments of the present invention;

FIG. 14 is a schematic plan view showing print patterns and the firstand the second print marks printed in first and second gravure-printingsteps according to the second modification of preferred embodiments ofthe present invention;

FIGS. 15A and 15B are diagrams showing steps of determining transittimes of the first print mark and the second print mark, respectively,in the second modification of preferred embodiments of the presentinvention;

FIG. 16 is a schematic perspective view showing a step of determining atransit time of a second print-mark-printing element provided on asecond gravure roll according to a third modification of preferredembodiments of the present invention; and

FIG. 17 is a schematic plan view showing a step of printing conductivepaste and step-reducing ceramic paste in a known method formanufacturing a ceramic electronic component.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A preferred embodiment of the present invention will be described belowwith reference to the accompanying drawings.

FIG. 4 is a schematic diagram showing a manufacturing apparatus of amultilayer ceramic capacitor according to a preferred embodiment of thepresent invention.

In the manufacturing apparatus 1 of the multilayer ceramic electroniccomponent, a composite sheet 2 including a supporting film composed of asynthetic resin such as polyethylene terephthalate, polypropylene, andpolyethylene naphthalate and a ceramic green sheet disposed on thesupporting film is conveyed as shown by the arrow B in the figure. Themanufacturing apparatus 1 of the multilayer ceramic electronic componentincludes first and second gravure-printing units 3 and 4 for performingfirst and second gravure-printing steps, respectively, in each of whichone side of the composite sheet 2 is printed.

The first gravure-printing unit 3 includes a first gravure roll 5 whichdefines a plate cylinder and a first impression roll 6. As shown in FIG.5A, which is a perspective view of the gravure roll 5, the gravure roll5 is cylindrical and includes a first print section 7 a provided alongthe external circumference 5 a of the gravure roll 5 and a predeterminedgap 5 b which extends along the axis of the gravure roll 5. In order toprint conductive paste on the ceramic green sheet and form internalelectrodes, a plurality of substantially rectangular recesses 7 b arearranged in the print section 7 a in a matrix pattern such that theyextend substantially parallel to the rotating direction of the gravureroll 5. Each of the recesses 7 b includes a plurality of cells (notshown), each cell being surrounded by a substantially rectangular wall.The shape of the recesses 7 b corresponds to that of electrodes requiredin the multilayer ceramic electronic component, and is not limited tobeing substantially rectangular. Although only one print section 7 a isshown in FIG. 5A, two or more print sections may also be provided.

In addition to the first print section 7 a, a first print-mark-printingelement 7 c which prints a first print mark used for correcting adisplacement of the composite sheet along the conveying directionthereof, which will be described below, is also provided on the externalcircumference 5 a of the first gravure roll 5. The shape of theprint-mark-printing element 7 c is not particularly limited. Inaddition, a first trigger-mark-printing element 7 d is provided in frontof the print-mark-printing element 7 c in the print direction.

In the first gravure printing step, the composite sheet 2 passes betweenthe gravure roll 5 and the impression roll 6 of the firstgravure-printing unit 3, and the conductive paste (first paste) suppliedin the recesses 7 b in the print section 7 a by a conductive-pastesupplier (not shown) is transferred onto the composite sheet 2. Theconductive paste is obtained by mixing conductive powder made of, forexample, Ag, Ag—Pd, Ni, Cu, Au, or other suitable conductive powderswith an organic vehicle.

The first gravure-printing unit 3 also includes rollers 8 a to 8 e whichare arranged to feed the composite sheet 2 to the position between thegravure roll 5 and the impression roll 6, and the composite sheet 2 isconveyed to the position between the gravure roll 5 and the impressionroll 6 via the rollers 8 a to 8 e. In addition, a roller 8 f is providedbehind the gravure roll 5, and the composite sheet 2 on which theconductive paste is printed is conveyed to a first drying device 9 viathe roller 8 f. The drying device 9 includes a suitable heater, and isprovided for drying the conductive paste printed on the composite sheet2.

In addition, rollers 10 a and 10 b are provided downstream of the dryingdevice 9, and the composite sheet 2 is fed to the secondgravure-printing unit 4 after the conductive paste is dried. The secondgravure-printing unit 4 includes a second gravure roll 11 and a secondimpression roll 12 for performing gravure printing.

As shown in FIG. 5B, similar to the first gravure roll 5, the secondgravure roll 11 is substantially cylindrical and includes a second printsection 11 b provided along the external circumference 11 a of thesecond gravure roll 11 and a predetermined gap 11 g which extend alongthe axis of the second gravure roll 11.

In order to print step-reducing ceramic paste on the composite sheet 2at regions where the conductive paste is not printed, the print section11 b includes a plurality of projections 11 c having approximately thesame shape as the printed conductive paste at positions corresponding tothe printed conductive paste and a grid-shaped groove 11 d whichsurrounds the projections 11 c and into which the step-reducing ceramicpaste is supplied. Although only one print section 11 b is shown in FIG.5B, two or more print sections may also be provided.

Similar to the first gravure roll 5, in addition to the second printsection 11 b, a second print-mark-printing element 11 f which prints asecond print mark used for correcting the displacement of the compositesheet along the conveying direction thereof is also provided on theexternal circumference 11 a of the second gravure roll 11. The shape ofthe print-mark-printing element 11 f is not particularly limited. Inaddition, a second trigger-mark-printing element 11 e is provided infront of the second print-mark-printing element 11 f in the printdirection.

In the second gravure printing step for eliminating the steps, thecomposite sheet 2 on which the conductive paste is printed passesbetween the gravure roll 11 and the impression roll 12 of the secondgravure-printing unit 4, and the step-reducing ceramic paste (secondpaste) supplied in the groove 11 d in the print section 11 b by astep-reducing-paste supplier (not shown) is transferred onto thecomposite sheet 2. The step-reducing ceramic paste is obtained by mixingceramic powder of, for example, dielectric ceramic, magnetic ceramic,glass, glass ceramic, or other suitable ceramic powders with an organicvehicle.

Rollers 13 a to 13 e and a compensator roll 28 are arranged to feed thecomposite sheet 2 to the position between the gravure roll 11 and theimpression roll 12.

The compensator roll 28 is configured so as to move in a direction shownby the arrow D in FIG. 4, and the position of the ceramic green sheetalong its length is controlled by moving the compensator roll 28. Inaddition, a roller 13 f and a second drying device 14 are disposeddownstream of the gravure roll 11. The construction of the second dryingdevice 14 is similar to that of the first drying device 9. The seconddrying device 14 includes a heater suitable for drying the step-reducingceramic paste applied by the second gravure roll 11.

In addition, rollers 15 a and 15 b are provided downstream of the seconddrying device 14, and the composite sheet 2 which is subjected to theprinting processes performed by the first and the second gravureprinting portions 3 and 4 is output along a direction shown by the arrowC.

As shown in FIG. 6, according to the preferred embodiment of the presentembodiment, the second gravure roll 11 is connected to a moving device20 which moves the gravure roll 11 along its axis for correcting thedisplacement between the conductive paste printed by the firstgravure-printing unit 3 and the step-reducing ceramic paste printed bythe second gravure-printing unit 4 in the width direction (directionperpendicular to the conveying direction of the composite sheet).Although not shown in FIG. 6, the moving device 20 includes areciprocating drive source 29 which moves the gravure roll 11 by adesired distance along its axis in accordance with a signal input from acontroller 24. The reciprocating drive source 29 may be a reciprocatingdrive device such as an air cylinder and a hydraulic cylinder or areciprocating drive mechanism obtained by combining a motor and arack-and-pinion system.

FIG. 2 is a schematic diagram showing the main portion of a system forcontrolling the position of the gravure roll 11 along its axis and theposition of the composite sheet 2 along its length according to thepresent preferred embodiment. As shown in FIG. 2, a trigger sensor 21and a first camera 22 are disposed in front of the second gravure roll11. The trigger sensor 21 is provided for detecting a first triggermark, and the camera 22 is provided for photographing a first printmark. The trigger sensor 21 and the first camera 22 are connected to afirst image processor 23, and the first image processor 23 is connectedto the controller 24.

When the trigger mark is detected by the trigger sensor 21, thecontroller 24 outputs a command to photograph the first print mark tothe camera 22. Then, an image of the first print mark obtained by thecamera 22 is processed by the image processor 23, and a signalindicating the position of the first print mark is input to thecontroller 24.

In addition, a trigger sensor 25, a second camera 26, and a second imageprocessor 27 are disposed downstream of the second gravure roll 11. Thetrigger sensor 25 is provided for detecting a second trigger markprinted by the second gravure roll 11, and the camera 26 is provided forphotographing a second print mark. The image processor 27 is connectedto the controller 24. When the controller 24 receives a signalindicating that the second trigger mark is detected by the triggersensor 25 after the second gravure-printing step, the controller 24drives the second camera 26 such that it photographs the second printmark. An image photographed by the second camera 26 is processes by theimage processor 27, and a signal indicating the position of the secondprint mark is input to the controller 24.

The controller 24 stores desired positions of the first and the secondprint marks, that is, desired positions of the ceramic green sheet alongits length and width.

Next, a method for manufacturing a multilayer ceramic electroniccomponent according to a preferred embodiment the present embodimentwill be described below with reference to FIGS. 1A to 1C and FIG. 3 inaddition to the above-mentioned drawings.

FIG. 1A is a schematic plan view of the composite sheet 2 after thefirst and the second gravure-printing steps are performed. In FIG. 1A,the width of the supporting film (dimension in a direction perpendicularto the arrow shown in the figure) is approximately the same as the widthof the ceramic green sheet. However, the width of the ceramic greensheet may also be less than that of the supporting film such that thesupporting film protrudes from the ceramic green sheet at both sidesthereof. In such a case, the first and the second trigger marks and thefirst and the second print marks may also be printed on the supportingfilm.

The first trigger mark 33 and the first print mark 34 are printed in thefirst gravure-printing step. As shown in FIG. 1B, only the first printmark 34 of the two print marks is printed after the firstgravure-printing step. The second trigger mark 35 and the second printmark 36 are printed in the second gravure-printing step.

As shown in FIG. 2, in the present preferred embodiment, the position ofthe first print mark 34 is determined by the image processor 23 afterthe first gravure-printing step and before the second gravure-printingstep. More specifically, when the first trigger mark 33 is detected bythe trigger sensor 21, the controller 24 drives the first camera 22 suchthat it photographs the first print mark 34. Then, the actual positionof the first print mark 34 is input to the controller 24.

The controller 24 calculates the difference between the actual positionof the first print mark 34 which is determined as described above andthe desired position thereof which is stored in the controller 24 inadvance, and moves the composite sheet 2 on the basis of the calculateddifference such that the distances q and r between the first and thesecond print marks 34 and 36 along the width and the length,respectively, shown in FIG. 1C become the same as desired distances Qand R, respectively. The movement of the composite sheet 2 is achievedby the above-described moving device 20 and the compensator roll 28.More specifically, the movement along the width of the ceramic greensheet is achieved by the above-described moving device 20 and themovement along the length thereof is achieved by adjusting the positionof the compensator roll 28 so as to eliminate the difference along thelength.

Accordingly, the composite sheet is moved such that the positionalrelationship between the first and the second print marks is optimizedbefore the second gravure-printing step is performed. More specifically,even when the first print mark is displaced from the desired position,the second mark is printed at an accurate position with respect to thefirst print mark. Therefore, in the second gravure-printing step whichis performed afterwards, print patterns are formed at desired positionswith high accuracy with respect to print patterns formed in the firstgravure-printing step. More specifically, the displacements between theprint patterns formed in the first gravure-printing step and thoseformed in the second gravure-printing step are reliably prevented.

Although the ceramic green sheet is moved by the moving device 20 andthe compensator roll 28 before the second gravure-printing step in thepresent preferred embodiment, it may also be moved during the secondgravure-printing step. More specifically, the ceramic green sheet may bemoved in the middle of the second gravure printing such that theaccuracy is increased in the second gravure-printing step which isperformed afterwards. In particular, in the case in which a plurality ofprint patterns are printed along the length in the secondgravure-printing step, distortion of the print patterns printed in thesecond gravure-printing step is prevented by moving the ceramic greensheet within the regions between the print patterns.

In the present preferred embodiment, however, the secondgravure-printing step using the gravure roll 11 is performed after theceramic green sheet is moved.

In the second gravure-printing step, the second trigger mark 35 and thesecond print mark 36 shown in FIG. 1A are printed. When the secondtrigger mark 35 is detected by the trigger sensor 25 at a positiondownstream of the second gravure roll 11, the controller 24 drives thecamera 26 such that it photographs the second print mark 36. Then, theposition of the second print mark 36 is determined by the imageprocessor 27, and is input to the controller 24.

The desired position of the second print mark 36 is stored in thecontroller 24 in advance. The controller 24 compares the positions ofthe first and the second print marks which are actually printed in thefirst and the second gravure-printing steps, respectively, with thedesired positions of the first and the second print marks stored in thecontroller 24, and moves the ceramic green sheet so as to eliminate thedifferences therebetween.

Since the ceramic green sheet is moved after the second gravure-printingstep so as to eliminate the differences between the positions of thefirst and the second print marks which are actually printed and thedesired positions of the first and the second print marks stored inadvance, the accuracy in the first and the second gravure-printing stepsperformed afterwards is greatly increased. In the present invention,however, the feedback control using the second print mark is notnecessary, and only the feedforward control using the first print markmay be performed.

In the present preferred embodiment, the distances between the first andthe second print marks 34 and 36 along the width and the length areaccurately adjusted to the desired distances Q and R, respectively, bymoving the gravure roll 11 along the width of the ceramic green sheetwith the moving device 20 and adjusting the position of the compensatorroll 28. Accordingly, as shown in FIGS. 7 and 8, in the secondgravure-printing step, the print patterns are printed at accuratepositions with respect to the print patterns formed in the firstgravure-printing step. In other words, the conductive paste and thestep-reducing ceramic paste are accurately printed such that they do notoverlap each other.

As shown in FIG. 8, in the composite sheet 2 which is subjected to theabove-described first and second gravure-printing steps, a ceramic greensheet 72 is formed on a supporting film 71. In addition, internalelectrodes 73 are formed on the ceramic green sheet 72 in the firstgravure-printing step, and a step-reducing ceramic member 74 is formedin the second gravure-printing step. Although the internal electrodes 73and the step-reducing ceramic member 74 are arranged without gapstherebetween in FIG. 8, predetermined gaps may also be provided betweenthe internal electrodes 73 and the step-reducing ceramic member 74.Alternatively, the step-reducing ceramic member 74 may also be arrangedsuch that it overlaps the internal electrodes 73 at the peripheral edgesof the internal electrodes 73 by a desired width.

The long composite sheet 2 is cut by a culling head (not shown) suchthat a film element including the ceramic green sheet 72, the internalelectrodes 73, and the step-reducing ceramic member 74 is separated fromthe supporting film 71. Then, a plurality of film elements obtained asdescribed above are laminated on a lamination stage or in the cuttinghead, such that a mother laminate 81 shown in FIG. 9A is obtained. Inthe mother laminate 81, a plain ceramic green sheet is provided at thebottom. In addition, another plain ceramic green sheet may also beprovided on the top.

In addition, the mother laminate 81 may also be formed by repeatingprocesses of culling the long composite sheet 2 along the print sectionsuch that a card-shaped sheet element is obtained, pressing thecard-shaped sheet element onto a plain ceramic green sheet placed on alamination stage such that the supporting film 71 faces upward, andremoving the supporting film.

Then, laminate units are obtained by cutting the mother laminate 81along its thickness, each laminate unit being used in a singlemultilayer ceramic capacitor, and a sintered ceramic component 92 shownin FIG. 9B is obtained by sintering each of the laminate units. Then, amultilayer ceramic capacitor 91 is obtained by forming externalelectrodes 93 and 94 on the ends of the sintered ceramic component 92.The laminate unit and the external electrodes 93 and 94 may also besintered simultaneously.

In the manufacturing method of the multilayer ceramic capacitor 91, theconductive paste and the step-reducing ceramic paste are printed asdescribed in the above preferred embodiment. Therefore, displacementsbetween the conductive paste and the step-reducing ceramic paste aregreatly reduced and the steps around the conductive-paste elements areeliminated.

Therefore, structural defects of the sintered components, such asdelamination, do not occur and the defect rate is effectively reduced.

In addition, the present invention may be applied not only to themultilayer ceramic capacitor, but also to various multilayer ceramicelectronic components such as a multilayer inductor, a multilayer noisefilter, a multilayer LC filter, and a multilayer composite module. Insuch cases, circuit elements can be obtained by forming via holes in theceramic green sheet and connecting the planar internal electrodepatterns.

First Modification of Preferred Embodiments

A method for manufacturing a multiplayer ceramic electronic componentaccording to a first modification of the above-described preferredembodiment will be described below with reference to FIGS. 10 to 12. Theconstructions of the first modification and second and thirdmodifications, which will be described below, are similar to that of theabove-described preferred embodiment except for the structure fordetermining the position of the second print mark after the secondgravure-printing step. Therefore, only differences between theabove-described preferred embodiment and the modifications will bedescribed below and explanations of constructions similar to that of theabove-described preferred embodiment are omitted.

As shown in FIG. 10, a trigger sensor 41 and a camera 42 are connectedto the image processor 27. The trigger sensor 41 is provided fordetecting the trigger-mark-printing element 11 e on the second gravureroll 11, and the camera 42 is provided for photographing the secondprint-mark-printing element 11 f on the second gravure roll 11. Morespecifically, in the present modification, the position of the secondprint-mark-printing element 11 f is determined using thetrigger-mark-printing element 11 e and the second print-mark-printingelement 11 f instead of using the second trigger mark and the secondprint mark printed on the composite sheet. Then, the position of thesecond print-mark-printing element 11 f is input to the controller 24.

Also in the present modification, the controller 24 stores desiredpositions of the first and the second print marks.

In the present modification, the first print mark 34 is printed on thecomposite sheet, as shown in FIG. 11, and the position of the firstprint mark 34 is input to the controller 24 as in the above-describedpreferred embodiment.

Similar to the above-described preferred embodiment, the controller 24moves the ceramic green sheet such that the second print mark is printedat a position where the distances between the first and the second printmarks along the width and the length are Q and R, respectively, on thebasis of the position of the first print mark 34 which is actuallyprinted. Accordingly, the ceramic green sheet is moved to a suitableposition before the second gravure-printing step. Therefore, in thepresent modification, even when print patterns printed in the firstgravure-printing step are displaced, print patterns printed in thesecond gravure-printing step are accurately positioned with respect tothe print patterns printed in the first gravure-printing step.

Next, when the trigger sensor 41 detects the secondtrigger-mark-printing element 11 e in the second gravure-printing step,the second print-mark-printing element 11 f shown in FIG. 12 isphotographed by the camera 42 and the position information thereof isinput to the controller 24. In addition, the time at which the secondprint-mark-printing element 11 f is photographed is also input to thecontroller 24. The controller 24 calculates the position of the secondprint mark on the basis of the received position information and thetime.

In the present modification, similar to the above-described preferredembodiment, the ceramic green sheet is moved so as to eliminate thedifferences between the desired positions of the first and second printmarks which are stored in the controller 24 in advance and the positionsof the first and second print marks which are actually printed beforethe second gravure-printing step is performed.

Accordingly, in the second gravure-printing step, the print patterns areprinted at accurate positions with respect to the print patterns printedin the first gravure-printing step.

In addition, since the positions of the second trigger mark and thesecond print mark are determined using the trigger-mark printing element11 e and second print-mark-printing element 11 f provided on the secondgravure roll 11 instead of using the second trigger mark and the secondprint mark printed on the composite sheet, the image process isperformed irrespective of the material of the second trigger mark andthe second print mark.

For example, when the second trigger mark and the second print mark arecomposed of the same ceramic material as the ceramic green sheet in thecomposite sheet, the image process of the second trigger mark and thesecond print mark printed on the composite sheet is often difficult.However, when the image process of the trigger-mark-printing element 11e and the second print-mark-printing element 11 f is performed, thecomparison between the second gravure roll 11 and thetrigger-mark-printing element 11 e and between the second gravure roll11 and the second print-mark-printing element 11 f is performedirrespective of the material of the trigger mark and the print mark.

The positions of the trigger-mark-printing element 11 e and the secondprint-mark-printing element 11 f and the positions of the second triggermark and the second print mark printed on the composite sheet are thesame unless displacement occurs due to sliding between the secondgravure roll 11 and the composite sheet

Second Preferred Modification

A second modification of the above-described preferred embodiment willbe described below with reference to FIGS. 13 to 16. In the secondmodification, as shown in FIG. 14, which is a plan view of the compositesheet after the second gravure-printing step, a first print mark 51 anda second print mark 52 are printed outside the print area after thefirst and the second gravure-printing steps.

The dimensions of the first and the second print marks 51 and 52 alongthe length of the composite sheet 2 change depending on the positionalong the width of the composite sheet 2. More specifically, thedimensions of the first and the second print marks 51 and 52 along thelength of the composite sheet 2 increases toward the center of thecomposite sheet 2. Accordingly, each of the first and the second printmarks 51 and 52 has a substantially triangular shape with its basefacing the center of the composite sheet 2.

In addition, as shown in FIG. 13, a first sensor 53 and a firsttime-measuring device 54 are placed in front of the second gravure roll11. The first sensor 53 is turned on while the first print mark 51 ispassing by the first sensor 53. The first time-measuring device 54measures the time interval during which the first sensor 53 is turnedon. More specifically, the first time-measuring device 54 measures thetransit time of the first print mark 51, that is, the time intervalduring which the first print mark 51 passes by the first sensor 53, andinputs the time interval to the controller 24. In addition, the time atwhich the first sensor 53 is turned on is also input to the controller24.

In addition, a second sensor 55 and a second time-measuring device 56are disposed behind the second gravure roll 11. The second sensor 55 isconstructed similarly to the first sensor 53, and is turned on while thesecond print mark 52 is passing by the second sensor 55. Accordingly,the controller 24 receives the transit time of the second print mark 52,that is, the time interval during which the second print mark 52 passesby the second sensor 55 from the second time-measuring device 56. Inaddition, the time at which the second sensor 55 is turned on is alsoinput to the controller 24.

As described above, the dimensions of the first and the second printmarks 51 and 52 along the length of the composite sheet change dependingupon the position along the width of the composite sheet. Therefore, thepositions of the first and the second print marks 51 and 52 along thewidth are determined by measuring the time intervals during which thefirst and the second print marks 51 and 52 pass by the first and thesecond sensors 53 and 55, respectively. This will be described in moredetail below with reference to FIGS. 15A, 15B, and 16.

As shown in FIG. 15A, the time interval i during which the first printmark 51 passes by the first sensor 53 is obtained when the first printmark 51 passes by the first sensor 53. In addition, as shown in FIG.15B, the time interval u is obtained and input to the controller 24 whenthe second print mark 52 passes by the second sensor 55. Since the firstand the second print marks 51 and 52 have shapes as described above,when the controller 24 receives the time intervals i and u, thecontroller 24 calculates the positions of the first and the second printmarks 51 and 52 along the width of the composite sheet. Then, thedistance w between the first and the second print marks 51 and 52 alongthe width of the composite sheet is obtained on the basis of thecalculation results. The controller 24 stores a desired distance betweenthe first and second print marks 51 and 52 along the width obtained whenthe first and the second print marks 51 and 52 are accurately printed inthe first and the second gravure-printing steps, respectively.Accordingly, the displacement along the width is reliably eliminated bymoving the second gravure roll 11 with the moving device so as toeliminate the difference between the actual distance between the firstand the second print marks 51 and 52 and the desired distance betweenthem.

In addition to the displacement along the width of the ceramic greensheet, the displacement along the length thereof is also eliminated.

More specifically, since the times at which the measurements of the timeintervals i and u are started are also detected by the sensors 53 and55, respectively, the distance v between the print marks 51 and 52 alongthe length is also obtained. Accordingly, when the controller 24 storesthe desired distance between the first and the second print marks 51 and52 along the length, the position of the ceramic green sheet in thesecond gravure-printing step along its length is corrected by moving thecompensator roll 28 by a distance corresponding to the differencebetween the above-described desired distance along the length and thedistance between the first and second print marks 51 and 52 along thelength which is obtained as described above

Third Modification of Preferred Embodiments

In the second modification, the second sensor 55 measures the timeinterval during which the second print mark 52 printed by the secondgravure roll 11 passes by. However, as shown in FIG. 16, the secondsensor 55 may also be arranged such that it measures a time interval Uaduring which a second print-mark-printing element 11 h provided on thegravure roll 11 passes by. In such a case, when the relationship betweenthe time interval Ua during which the second print-mark-printing element11 h on the gravure roll 11 passes by and the position at which thesecond print mark is actually printed is determined in advance, theposition at which the second print mark is printed is determined on thebasis of the time interval Ua. Other constructions of the thirdmodification are the same as those of the second modification.

Other Modifications of Preferred Embodiments

In the above-described preferred embodiments, only one camera isarranged behind the gravure roll 11 for photographing the first and thesecond print marks. However, the first and the second print marks mayalso be photographed with different cameras. More specifically, twocameras may be arranged behind the second gravure roll 11 in addition tothe camera for photographing the trigger mark.

In addition, in the second modification, two sensors for measuring thetime intervals during which the first and the second print marks pass bymay be arranged behind the second gravure roll 11.

In addition, according to the present invention, only the position ofthe composite sheet along the width thereof may be controlled by movingthe second gravure roll along its axis.

In the above-described preferred embodiments and modifications, thefirst paste is a conductive paste and the second paste is astep-reducing ceramic paste. However, the first paste may be astep-reducing ceramic paste and the second paste may be a conductivepaste. In addition, both of the first and second pastes may be aconductive paste. The first and second pastes are both conductive when,for example, electrode patterns of different shapes are formed of thefirst and the second pastes, a structure is formed using conductivepastes of different materials, or double coating is required.

The present invention is not limited to multilayer ceramic electroniccomponents, and may also be applied to methods for manufacturing otherceramic electronic components.

The present invention is not limited to the above-described preferredembodiments, but can be modified within the scope of the attachedclaims. Further, the technologies disclosed in the above-describedpreferred embodiments can be used in combination, as desired.

1. A method for manufacturing a ceramic electronic component,comprising: a preparation step of preparing a long composite sheetincluding a supporting film and a ceramic green sheet disposed on thesupporting film; a first gravure-printing step of applying first pasteto the ceramic green sheet in a first region of the ceramic green sheetby gravure printing; and a second gravure-printing step of applyingsecond paste to the ceramic green sheet in a second region of theceramic green sheet by gravure printing; wherein a first print mark isformed on the ceramic green sheet or the supporting film in the firstgravure-printing step; a second print mark is formed on the ceramicgreen sheet or the supporting film in the second gravure-printing step;and actual transit times of the first and the second print marks formedin the first and the second gravure-printing steps, respectively, arecompared with desired transit times of the first and the second printmarks, and a subsequent second gravure-printing step is performed inaccordance with the result of the comparison.
 2. A method formanufacturing the ceramic electronic component according to claim 1,wherein the subsequent second gravure-printing step is performed afterthe ceramic green sheet is moved along at least one of the width and thelength thereof in accordance with the result of the comparison or whilethe ceramic green sheet is being moved along at least one of the widthand the length thereof in accordance with the result of the comparison.3. A method for manufacturing the ceramic electronic component accordingto claim 1, wherein a first sensor and a first measuring device are usedfor determining the transit time of the first print mark.
 4. A methodfor manufacturing the ceramic electronic component according to claim 1,wherein the dimension of the first print mark extending along the lengthof the ceramic green sheet changes along the width of the ceramic greensheet.
 5. A method for manufacturing the ceramic electronic componentaccording to claim 1, wherein the dimension of at least one of the firstprint mark and the second print mark extending along the length of theceramic green sheet changes along the width of the ceramic green sheet.6. A method for manufacturing the ceramic electronic component accordingto claim 1, wherein the first print mark has a substantially triangularshape.
 7. A method for manufacturing the ceramic electronic componentaccording to claim 1, wherein the first print mark and the second printmark have substantially triangular shapes.
 8. A method for manufacturingthe ceramic electronic component according to claim 1, wherein one ofthe first paste and the second paste is a conductive paste and the otherof the first paste and the second paste is a step-reducing ceramicpaste.
 9. A method for manufacturing the ceramic electronic componentaccording to claim 1, wherein the first paste and the second paste areconductive pastes.